LinuxBSDos.com posted a tutorial about setting up a dual boot with Linux Mint 9 and Ubuntu 10.04

In some situations, you may want to install more than one operating system on a computer. One method of accomplishing that is to utilize virtualization applications to run one atop the other. Another method, one that does not require specialized hardware or software, is to create a multi-boot scheme – installing multiple operating systems on one or more hard drives (on the same computer.) Dual-booting is a multi-boot example involving two operating systems.

This tutorial gives you the instructions needed to dual boot Linux Mint 9 and Ubuntu 10.04 Desktop. Unless you intend to create custom partitions, very little effort is required on your part. The installer does virtually everything.

  How to dual boot Linux Mint 9 and Ubuntu 10.04